Reversible swing hammer crusher with adjustable breaker plates



Aug. 9, 1949.

F. JQWRIGHT REVERSIBLE SWING HAMMER CRUSHER WITH ADJUSTABLE BREAKERPLATES Filed May 6, 1947 3 Sheets-Sheet 1 Aug. 9, 1949.

F. J. WRIGHT 2,478,733 REVERSIBLE SWING HAMMER CRUSHER WITH ADJUSTABLEBREAKER PLATES Filed May 6, 1947 s Sheets-Sheet 2 /44. A /am Aug. 9,1949. F. J. WRIGHT 2,478,733

- REVERSIBLE SWlNG' HAMMER CRUSHER WITH ADJUSTABLE BREAKER PLATES FiledMay 6., 1947 3 Sheets-Sheet 3 IN VEN Tole FEED J. WEIGHT,

HTT'Y mate Ana 9. 1m

UNITED STATES PATENT OFFICE REVERSIBLE SWING HAMIWER CRUSHEE WITHADJUSTABLE BREAKER PLATES Fred J. Wright, Columbus, Ohio, alsignor toThe Jeflrey Manufacturing Company, a corporation of Ohio Application May6, 1947, Serial-N0. 748,365

to and from the power driven rotor for changing the relationship of theco-operating material reducing surfaces of the power driven rotor andthe material reducing means.

It is another object of my invention to provide an improved materialreducing apparatus of the hammer mfll type which includes a power drivenmaterial reducing rotor operating within a material reducing chamber anda reducing means adapted to co-operate therewith mounted upon arms forbodily movement about parallel axes to and from'the powerfdrivenmaterial reducing rotor for changing the relationship of the cooperatingmaterial reducing surfaces of the power driven rotor and he materialreducing means wherein one of t e arms which carries the reducing meansforms a breaker wall in the material reducing chamber.

Other objects of the invention will appear hereinafter the novelfeatures and combinations being set forth in the appended claims? In theaccompanying drawings,

Fig. 1 is a side view in elevation of a material reducing plantincorporating the features of my invention, a portion of a conveyerthereof being shown in dotted lines;

Fig 2 is a view in section through the material reducing plant seen inFig. 1 but with the conveyer portion shown in elevation, the sectionbeing taken on line 2-4 of Fig. 3; and.

Fig. 3 is a view in section, the section being taken on line 3-3 of Fig.2.

Briefly described, the material reducing plant 80 shown in the drawingsincludes an outer housing or casing H within which there is an innerhousing, compartment or material reducing chamber i2. Within andadjacent the bottom of the inner housing, compartment or materialreducing chamber I: there is a reversible power driven material reducingrotor assembly IS. The

inner housing, compartment or material reducnewable liner plates 21.

2 therein by the material reducing rotor i3 and walls of the materialreducing chamber I! which co-operate with the rotor iii to reduce thematerial.

Below the inner housing, compartment or material reducing chamber I2 isa reduced material receiving chamber i'5 into which material reduced inthe reducing chamber I2 falls Or is discharged. As shown in thedrawings, the bottom of the reduced material receiving chamber I5 isformed by the traveling top run I6 of a power driven conveyer ll, thefoot section only of which is shown.

Referring in detail to the construction of the plant It, the outerhousing or casing of the material reducing plant it forms the main framel8 of the upper portion of the material reducing plant it, which portionof the plant includes a hammer mill type grinder for reducing,-breaking,grinding and otherwise reducing material fed into the material reducingplant l0. Main frame it includes a pair of opposite upright wall membersl9 and 20 of similar shape IWhiCh are connected as by welding alongtheir bottom edges to a rectangular frame or base 2|. Extending betweenthe opposite upright wall members l9 and 20 above the rectangular frameor base 2! there is a pair of oppositely disposed connector members 22each of which is secured to both of the opposite upright wall members l9and 20 and to the rectangular frame or base 2| as by welds.

The opposite upright wall members l9 and 20- form end walls of thematerial reducing chamber l2 and of the feed chute i4 and the areasbetween the opposite upright wall members I! and 20 above the connectormembers 22 and at each side of the feed chute M are closed by suitablecovers 23 each of which includes an inspection opening 24 closed by aplate 25 bolted to the outside of each cover 23.

The top walls of the material reducing chamber l2 are formed of a pairof similar relatively heavy plates 26 which extend between the oppositeupright lwall members l9 and 20 and are welded at their ends thereto,thereby forming fixed walls of the -material reducing chamber l2 andfixed members of the main frame I 8. The inner or centermost edges offixed plates 26 are each welded to a bottom side edge of the feed chutei4. Wall members l9- and 20 in those areas where they form the end wallsof the material reducing chamber l2 have bolted thereto re- It may benoted here that the opposite upright wall members l9 and canvas 26 andthe top walls of reducing chamber I2 formed by plates 26 are the onlywall members of the material reducing chamber I2 which are notadjustable.

That. part of the which is above the rectangular frame or base 2| issymmetrical about an upright plane, indicated at 26 inFig. 2, whichplane extends through the axis of the rotor assembly I3 and the feedchute or opening I4, therefore, a description of the right half of thematerial reducing chamber I2, as seen in Fig. 2, will also describe theleft side thereof.

A portion of the right hand wall of the material reducing chamber I2 isformed by a breaker plate 29 which may be considered as a generallyupright substantially flat arm having an inner breaker face or surface30. Each breaker plate or arm 29 is spaced inwardly of one of theopposite side walls of the housing or main frame I6 and these breakerplates or arms 29 form opposite walls of the material reducing chamberI2 and each co-operates with the adjacent .outer wall of the housing ormain frame II, or more specifically with cover members 23 thereof, toprovide an air passage 66 therebetween that is more fully describedhereinafter. Each breaker plate or arm 29 is pivotallycarried at itsupper end upon a shaft 2| which extends between and into alignedopposite openings in the opposite upright wall members I9 and 29 each ofwhich openings is closed at the outside by a disc or plate 22 bolted tothe outside of wall members I9 and 26. Breaker plate or arm 29 pivotsupon and about the axis of the shaft H and the uppermost end of itsinner or material reducing surface 36 is formed as an are about the axisof shaft 31 so that the surface 36 will co-operate with the lower oroutermost edge of plate 26 as the breaker plate or arm 29 is swlmg uponits pivot shaft 2| to maintain a close fit between the plate 26 andbreaker plate or arm 29 in order that there will be at most only a verysmall gap between the plate 26 and arm 29 through which material mightbe thrown out of thematerial reducing chamber I2. Below the breakerplate or arm 29 and pivotally connected thereto by a shaft or pivot pin33 is a material reducing chamber wall portion or member in theform of agrate 34 that forms an extension of the breaker plate or arm 29 throughwhich it is supported. Grate 24 includes 8. lug or ear 36 by which it ispivotally connected through a pivot shaft, rod or pin 39 to the lowerend of a pair of spaced arms 36 the upper ends of which are mountedupona pivot shaft, rod or pin 31 which, like pivot shaft, rod or pin 3i,extends between and into aligned openings in the opposite upright wallmembers l9 and of main frame I9 which are closed by discs 38, seen onlyin Fig. 1. I

The axes of pivot shafts, rods or pins 3|, 33, 31 and 39 are parallelwith respect to one another and the opposite walls I9 and 26 of the mainframe I9 form fixed means supporting the pivot pins 3| and 31 aboutwhich the arms 29 and 36 swing. The lower ends of arms 29 and 36 arepivotally connected by the grate 34 which is swingable therewith wherebythe fixed opposite wall members I9 and 26, arms 29 and 36, and grate 34form, as seen in Fig. 2, a parallelogram wherein the arms 29 and 36 andthe grate 34 swing between the fixed opposite wall members I9 and 26 toadjust the position of the grate 34 to and from the rotor.

In the embodiment of the apparatus shown in material reducing plant IllI carrying and adiusting the position of the grate be a trueparallelogram. In fact. in certain instances it is advantageous that thespacing be such that the grate will not remain in the same generalupright position as it is adjusted with respect to the rotor assembly IIin order that the distance between the co-operating surfaces of thegrate and rotor adjacent the heel and toe,

respectively, of the grate may bechanged with' respect to one another asthe grate is moved to and from rotor assembly I3.

Grate 24 is provided with an ear or lug 49 adapted to receive the end ofan adjusting bolt 4| that extends outwardly through a bar 42 and islocked thereto by a pair of nuts 43, one of which is disposed on eachside of the bar 42.

Bar 42 extends between'the opposite upright wall members l9 and 23 ofmain frame I I and each end thereof is provided with an outwardlyextending boss or trunnion member 44 (see P18. 2) which is received inan opening in the wall members I9 and 29 of main frame It. The openingswhich receive the bosses or trunnions 44' are closed at their outsldesby plates or discs 46, seen in Fig. 1. Access to the nuts 42 foradjusting the position of grate 34 with respect to the material reducingrotor assembly I3 is hadthrough the inspection opening 24 in main framecover member or closure 23.

Within the material reducing chamber I2 and above the reversiblematerial reducing rotor assembly I3 is a pivotally mounted material flowdirecting or diverting member in the form of a butterfly valve 46 whichextends across the material reducing chamber I2 and has its upper endextending into the feed .chute or opening I4. The material directing ordiverting member 44 includes opposite walls 41 removably secured to ashaft 46 which forms the pivotal mounting means of the materialdirecting or diverting member 46. Shaft 48 extends between the oppositeupright walls l9 and 26 and is carried in aligned openings therein oneof which is closed by plate or disc 49, seen in Fig. 3. It is to benoted that the axis of shaft 43 is parallel with the axis of the rotorI3 and lies in a vertical plane passing through the axis of the latter.The end of shaft 46 opposite plate or disc 49 carries a handle or lever56 by which anoperator may change the position of the material directingor'diverting means 46 to cause it positively to direct or divertselectively, all of the material entering the material reducing chamberI2 throughthe feed chute or opening I4 into the material reducingchamber I2 toward that breaker surface 30 of that breaker plate, sidewall or arm 29 with which the rotor I3 is cogipeirating to break orotherwise reduce the mate- It is to be noted, as seen in Fig. 2, thatwhen the material directing or diverting member 46 is in the positionshown, that portion of the material reducing chamber I2 which is to theleft of the lower right hand end of the material directing or divertingmember 46 is completely covered and that all of the material enteringthe savages the swingable material directing or diverting butterflyvalve 46 which extends below the axis of shaft. Since the axis of pivotshaft 48 of the v material directing or diverting butterfly valve 46lies in a vertical plane through the axis of rotor IS the bottom, orthat portion thereof which extends below the axis of shaft 48 will swingthrough the said vertical plane when the position of the butterfly valve46 is shifted for selectively positively directing all of the materialentering the reducing chamber l2. The reasons for directing materialinto the chamber l2 a distance A beyond plane 28 toward the breakerplate or arm 89 with which the rotor assembly is co-operating to breakor reduce material is fully explained hereinafter.

The handle or lever 59 by which the material directing or divertingmeans 46 is adjusted preferably has secured thereto a pair of ears orlugs 5| one of which co-operates in either position of the-materialdirecting or diverting means with one of a pair of ears or lugs 52 onmain frame wall l9. Ears 5| and 52 include openings adapted to alignwith each other for receiving a locking bolt 53 for insuring that theposition of the material directing or diverting means may not beaccidentally or inadvertently shifted during operation of the materialreducing apparatus.

Each of the opposite upright main frame wall members |9 and 29 adjacentthe bottom of that area thereof which forms an end wall of the materialreducing chamber I2 as well as the liner plates 21 carried thereby formsa circular opening 56. Theopenings 54 in the side wall members l9 and 29are axially aligned and receive end flywheel members 55 of the rotorassembly N. The outside of each flywheel receiving opening 54 of thewalls l9 and 29 is closed by acircular disc or plate 56 having a centralshaft receiving opening 51. Each disc or plate 56 is bolted about itsperiphery to a ring 58 which is welded to the outside-wall of the mainframe l8.

The rotor assembly I3 includes a shaft 59 the left hand end of which, asseen in Fig. 3, carries a ring 69 which co-operates with an inwardlyextending peripheral shoulder formed about the opening 51 in plate 56 toform a labryinth type lubricant seal. The left hand end of shaft 59 alsoincludes a shouldered portion which receives a self-aligninganti-friction bearing 6| that is fixed upon the shouldered portion ofthe shaft 59 by a nut-62 which carries a removable ring 63. Bearing 6|is supported by disc or plate 56 through a cap 64 bolted to the disc orplate 56 in which there is formed a central opening having a peripheralshoulder which co-operates with the removable ring 63 to form an outerlabyrinth type lubricant seal for the compartment in which the bearing6| is carried. The outermost or left end of shaft 59 is adapted toreceive a driving pulley .65, which is shown in phantom lines in Fig. 3,that is keyed to the shaft .59 by a key 6-6.

- The right hand end of shaft 59 carries a ring 69' which co-operateswith an. inwardly extending peripheral shoulder formed about the centralshaft opening in the right hand disc or. plate 56 andthe right hand endof shaft 59 is carried by the right hand disc 56 through a self-aligning6 the left hand opening 54 as fully described here.- inafter. Shaft 59includes a heavy center portion 68 which is provided at each Of its endswith a shoulder 69 against which the heavy flywheels 55 are clamped bythree clamping members in the form of rods or tie bolts 19. Between t eflywheels 55 the body of the rotor assembly I! includes a plurality oftriangular Plates H spaced apart by spacercollars 12 carried upon theclamping members or rods 19. The apices of triangular plates II arealigned and bored to form three axially aligned bores through the bodyof the rotor I3, each adapted to receive a pin, rod or shaft 18 uponwhich there are pivotally or swingably mounted hammers 14 which extendoutwardly from between the triangular plates I I. The ends of the pinsor shafts 13 are received in and held against axial movement by socketsformed in the flywheels 55. Preferably each flywheel is keyed to theshaft 59 by a key 15 and the trian gular plates II are keyed to theshaft 59 by a key 16.

The hammers 14 of the rotor assembly i3 may be replaced by removing theclosure disc 56 of the right hand opening 54, cap 61 and the shaftsupporting bearing 6| as a unit from the wall 29 and the right hand endof shaft 59 to expose the right hand flywheel 55 which may then beremoved from the rotor shaft 59 by removing nuts 11 from the ends ofclamping bolts or tie rods 19. With the right hand flywheel 55 removed,pins I3 may be withdrawn from the hammers 14 and plates ll of the rotorbody and new hammers 14 may be inserted in place of the removed hammers14 as each pin or shaft 13 is replaced in the rotor body. When thehammers 14 have been renewed the flywheel 55, disc 56, cap 61 andbearing 69 may be replaced and the machine is ready for operation. Ifdesired, the entire rotor assembly |3 may be removed bodily from thereducing chamber I2 by removing the bolts which secure the left handdisc or plate 56 to the left hand wall I9 and withdrawing the rotor fromthe chamber |2 through the left hand opening 54.

While I have shown the hammers 14 as being swing hammers, it is to beunderstood that the hammers or elements 14 may be of any desired shapeand that they need not be pivotally mounted to the rotor body. v

The portion of the plant |9 above described is carried by and above apair of spaced supports 18, herein shown as being of cast concrete. Theconveyer I 1 is positioned between the supports 18 and is directly belowthe reducing apparatus. Between the bottom of the rectangular frame orbase 2| of main frame l8 and the upwardly travelin top run I'6 of theconveyer I! there is a depending boot-19 which co-operates with thewalls of main frame I8 and the upper traveling run I6 of the troughedconveyer I! to form the reduced material. receiving chamber l5. Boot-l9includes a pair of inwardly downwardly sloping side walls and aninwardly downwardly sloping end wall 8| each of which, adjacent itslower edge,

carries a resilient strip or apron 82 adapted to ride with a lightpressure upon the top surface of the upwardly traveling top run or belt|6 of conveyer H to seal the upwardly traveling runor belt l6 to thewalls 89 and 8| so, as substan tially to prevent the loss or egress ofmaterials and gas from the reduced material receiving chamber |5 betweenthe walls 89 and 8| and the conveyer run l6. a v

As seen in Figs. 1 and 2, the side walls 89 of depending boot "extendsidewardly in the direcquently a hazardous condition.

tion of travel of the upwardly traveling top run ll of conveyer II toform an elongated tapering boot It, the top member of which is formed bya plate It spaced above the conveyer. The bottom of boot it is formed bythe upper traveling run of troughed belt II. which co-operates with adepending flexible curtain 82' at the right side of boot .3 to form avariable size outlet opening therein which co-operates with the troughedtraveling run l6 of the conveyer I1 and reduced material which is beingconveyed thereby from the reduced material receiving chamber ii to forma variable size substantially gas tight opening, thesize of which varieswith the quantity of material being conveyed upon the conveyer and whichmaterially restricts the egress of gas from the reduced materialreceiving chamber I! while permitting the troughed conveyer run II andthe reduced material carried thereby to be conveyed from the chamber.

The opposite side walls of feed chute M are formed by a plurality ofdownwardly inwardly, sloping louvre members 85 between which there arepassageways that open directly into ducts or passageways 88 formed bythe mainframe II, the wall members of the material reducing chamber, andthe cover members 23. Passageways or ducts 8i connect at their lowerends directly with the reduced material receiving chamber II.

It is well known that the rotor assembly of a material reducingapparatus or grinder, when operating, functions as an impeller or blowerand forces air or gas out of the apparatus and that when the apparatusis reducing material the air or gas impelled by the rotor will flow outof the apparatus with material that has been reduced. Air or gasexhausting from the material reducing apparatus with the reducedmaterial that is relatively dry creates a dusty, and fre- I provide forsubstantially closing or sealingthe material reducing apparatus againstthe egress or loss of gas while conveying reduced material therefrom bya conveyer, a portion of which is in or operates within the apparatusand. is adapted to receive and convey reduced material exhausted intothe closed reduced material receiving chamber from the material reducingchamber through a variable size opening which materially restricts orsubstantially prevents the egress of gas from the chamber with or aboutthe reduced material, and in my apparatus I have provided for theunrestricted passageof all of the air impelled by the rotor assemblyback to'the material reducing chamber. In the embodiment of my inventionshown in the drawings the gas impelled by the rotor assembly I! into thereduced material receiving chamber ii is returned to the reducingchamber I 2 through the passageways, ducts or conduits 86 formed by thebreaker plates 29, their grates 34 and the adjacent wall of the housingor main frame It and thepassageways between the louvres II into the feedchute II where it flows with material to be reduced into the reducingchamber i2.

'Referring again to the aterial reducing chamber l2 and the rotor.assembly "which is between and separates the chamber I! from the reducedmaterial receiving chamber I5, I have found that in material reducers orgrinders of the reversible rotor type, material which is fed into thematerial reducing chamber to that side of the upright plane 28 which isopposite the breaker wall or surface 30 with which the material reducinghammers or elements of the rotor II are co-operating to reduce material,will be thrown or knocked upwardly into the feed chute or opening II,and that under certain conditions the material being thrown or knockedupwardly by the rotor and the material flowing in the chute it will Jamin the chute and prevent or materially interfere with the feeding ofmaterial into the material reducing chamber I2. I have also found thatwhen all of the material is caused to enter the material reducingchamber It to that side of the upright plane 28 which is ad- Jacent thatbreaker plate or arm 29 with which the material reducing hammers orelements of the rotor are co-operating to reduce material, the cloggingtendencies above described are materially reduced. I have further foundthat in certain instances it is desirable that material entering thechamber i2 should be deflected to or caused to be struck by the reducingelements or hammers ll of the rotor assembly it to that side of theplane 28 which is in the direction of rotation of the material reducinghammers or elements of the rotor and adjacent that breaker plate or arm29 with which the material reducing elements are co-operating to reducematerial at least the distance herein designated A, which distance is atleast equivalent to the width (indicated at A in Fig. 2) of the widestmaterial reducing element carried by the rotor it since, as hereinafterexplained, material struck by the reducing elements or hammers I4 isknocked generally tangentially from the circle or cylinder defined bythe paths of the rotating reducing elements or hammers I4 and when thematerial is struck by the hammers the distance A, above described, toone side of the plane 28, the material is thrown or knocked sidewardlyrather than vertically upwardly into the feed chute ll.

It will be seen that when the rotor assembly I! is being driven, thematerial reducing elements thereof define a cylinder (indicated byphantom line 9| in Fig. 2) and that material which comes against orwithin the periphery of cylinder ll will be reduced by impact andknocked generally tangentially from the cylinder by the hammer elementsH. I have further found that when material fed into the materialreducing chamber I2 is deflected sidewardly in the direction of rotationof the rotor at least to the point of tangency of a plane tangent to thecylinder ll defined by the moving reducing elements of the rotor andintersecting the breaker surface 30 of the working breaker wall or armII with which the hammer elements are co-operating to reduce material atmost at a right angle above the tangent plane and the generally uprightbreaker surface 30, that even when sticky material such, for example, asmoist iron ore is being reduced, there is substantially no tendency ofthe material to clog the feed chute or opening it.

Referring to Fig. 2, the tangent plane above described is indicated at81, the point of tangency with the cylinder defined by the movingreducing elements is indicated at 88, and the angle between the tangentplane 81 and the working breaker surface 30 is indicated at B. Dottedline 8! indicates the left boundary of a stream of material entering thematerial reducing chamber I2 through the feed chute or opening H whichhas been deflected by the material directing or diverting member I.

A worn hammer element is indicated in dotted lines in Fig. 2 at 80,which hammer has been worn by impacts with material in the reducing 9chamber. I have found that each of the hammers wears so that the workingor front face 9| thereof which strikes the material wears to a curvedsurface, such as indicated at 92, and as the original sharp corners ofthe hammers wear to form the curved surface there is a tendency for.them to knock or throw material which they strike sidewardly andoutwardly from the rotor, thus, as seen in Fig. 2, when the hammer arenew they will throw the materialy tangentially therefrom toward thebreaker surface 30 with which they are co-operating substantially at theacute angle B indicated in Fig. 2 of the drawings and as the hammersgradually wear, the material is thrown outwardly and upwardly againstthe breaker surface 30 with the angle B gradually approaching a. rightangle, the upward movement being in proportion to the amount of wear ofthe hammers. When the material is deflected by the material directing ordiverting means 46 to the point of tangency 88 material which is thrownby the worn hammers will be thrown against the breaker surface 30substantially at a right angle thereto and therefore not in a path whichwill cause material entering the reducing chamber l2 through the feedchute or opening it to become jammed in the feed chute oropening 64thereby substan tially completely eliminating the detrimental effect ofan accumulation of material within the feed chute or opening it. Itwill, of course, be seen that the material being thrown directly againstthe breaker surface 30 by the rotor will prevent major accumulations ofmaterial thereon and within the 'material reducing chamber l2. Theco-operating ears or lugs 5i and 52 associated respectively with mainframe wall l9 and handle or lever 50 of the material directing ordiverting member E6 preferably also form electrical circuit breakers,not shown, which are connected into the power supply lines of theelectric motor, not shown, which drives the rotor.

The circuit breakers are connected into the power supply lines so as toreverse the direction of operation of the driving motor in accordancewith the position of setting to which the material directing ordiverting member 46 is swung by the handle or lever 50, that is, whenthe material directing means is swung to the position shown in Fig. 2the power supply lines are connected to the driving motor so that itwill operate in a direction to drive the rotor assembly l3 in aclockwise direction and when the material directing or diverting memberis swung to the position in which it directs material to the left, asseen in Fig. 2, the power supply lines to the motor will be reversed bythe circuit breakers of which ears or lugs 50 and 5| form parts to drivethe rotor as- .sembly in a counter-clockwise direction. It will be seenthat because of the described electrical circuit, the direction ofrotation of the rotor assembly I3 is determined by the position of thematerial directing or diverting member 46.

In operaton, with the rotor assembly l3 being driven at reducing speed,material to be reduced is fed into the reducing chamber i2 through thefeed chute or opening l4 wherein it is reduced and discharged into thereduced material receiving chamber l5. It may be noted here that thecross bars or plates 93 of each grate 34 are so arranged that the planesof their outside surfaces 95 are substantially tangent with the cylinder94 defined by the rotating hammers 14 of the rotor assembly i3. Becausematerial is thrown generally tangentially by the hammer elements, re-

, l0 duced material which is thrown toward the grates 34 may passdirectly through the spaces between the bars or plates 93 withoutclogging the passageways between the bars or plates 93 of the grates 34.Material which is discharged into the reduced material receiving chamberI5 falls upon the upwardly moving top run or belt I6 of the conveyer llwhich is within the reduced material receiving chamber l5 and isconveyed thereby sidewardly through the boot 83 and through the variablesize discharge opening therein which is formed by the flexible curtain82', which curtain preferably drags or rides upon the top of thematerial being conveyed in the troughed belt l6 and materially restrictsor seals the reduced material receiving chamber I5 against the egress ofair or gas which is being impelled by the rotor assembly IS. The air orgas which is impelled by the rotor assembly l3 flows upwardly in theducts 86 which are in communication with the reduced material receivingchamber l5 and enters the feed chute or opening [4 through the passagesbetween the louvres 85 where the air flows downwardly in the feed chuteor opening I l and is diverted sidewardly by the material directing ordiverting means 46 as it flows back into the reducing chamber l2. Thisfeature of my material reducing apparatus is particularly advantageousin that it tends to reduce air or gas pressure within the reducedmaterial receiving chamber 45 and to reduce the horse power required todrive the apparatus since all of the air or gas which is caused to flowby the rotor assembly i3 is re-circulated.

The positions of the grates 34 may be adjusted with respect to thematerial reducing elements of the rotor assembly it to change or altertheir positions with respect thereto for producing ground material ofdifferent size ranges. When one side of the material reducing hammerelements It becomes worn, the direction of operation of the apparatusmay be reversed which is substantially the full equivalent of renewingthe hammers 14 since those surfaces which were the backs of the hammersnow become the Working faces thereof. It will also-be seen that with myapparatus the right grate, as seen in Fig. 2 for example, may beadjusted to such position with respect to the rotor l3 that when therotor is driven in a clockwise direction the material will be reduced orground to a relatively fine condition and that the grate on the leftside of the machine is inoperative. The grate on the left side of themachine may be adjusted to cause the reducing apparatus to produce acoarser finished product and thus by merely reversing the direction ofoperation of the machine it may be caused to produce selectively arelatively fine or a relatively coarse finished product.

It will also be seen that as each of the grates 34 is adjusted, theupright angular position of its supporting breaker plate, wall or arm 29will change and that as the grate 3 5 is adjusted away from the rotorassembly I 3, its supporting breaker plate, wall or arm 29 will move toa position which is more nearly verticaL. This is advantageous becausethe more nearly vertical the position of the breaker wall or arm 29, thegreater is its tendency to deflect the material thrown against it by thehammer elements 14 back into the path or cylinder =94 defined by therotating hammers.

Obviously those skilled in the art may make I various changes in thedetails and arrangement of parts without departing from the spirit andscope of the invention as defined by the claims 11 hereto appended and Iwish therefore not to be restricted to theprecise construction hereindisclosed.

Having thus described and shown an embodiment of my invention, what Idesire to secure by Letters Patent of the United States is:

1. A grinder for reducing material including means forming a main frame,a material reducing chamber, wall means forming a side wall of saidreducing chamber, pivot means supporting said wall means from said mainframe for swinging movement about an axis, a power driven rotor in thebottom of said reducing chamber, material reducing elements carried bysaid rotor adapted to reduce material by impact and crushing. gratemeans carried by said wall means, said grate means including a faceadapted to co-operate with said reducing elements for crushingmaterial,pivot means connecting said grate means to said wall means for movementabout an axis parsaid second means, all of said pivots lying on parallelaxes whereby said grate means may be moved to and from said rotorthereby changing the angular position of said wall means and theposition of the grate means with respect to the material reducingelements.

. 2. A grinder for reducing material including means forming a mainframe, a material reducing chamber, wall means forming a side wall ofsaid reducing chamber, pivot means supporting said wall means from saidmain frame for swinging movement about an axis, a power driven rotor inthe bottom of said reducing chamber, material reducing elements carriedby said rotor adapted to reduce material by impact and crushing, gratemeans carried by said wall means, said grate means including a faceadapted to co-operate with said reducing elements for crushing material,pivot means connecting said grate means'to said wall means for movementabout an axis parallel to the supporting pivotal axis of the latter,

13 a second means oo-operating with said we! meanssupportingsaidgratemeansfmmssid mainframe forswingingmovement,pivotmeansconnectingsaiiiseveondmeanstosaiiiinainframs,

pivotmeansconnectingsaidgratemeanstosaid secondmeans.allofsaidpivotslyingonparallel axes whereby said grate means may bemoved to andfromsaidrotortherebyohanginlthea'nmlar position of said wallmeans and the position at the grate means with respect to the materialreclucing elements, and adjusting means for adiusting the positions ofsaid wall and grate means as aforesaid.

FRED J. WRIGHT.

REFERENCES CITED The following references are of record in the file ofthis patent:

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